call static method given a class object in java

Question

If

class MyClass {
    public static void main(String[] str) {
        System.out.println("hello world");
    }
}

// in some other file and method
Class klass = Class.forName("MyClass");

How can I call MyClass.main? I do not have the string "MyClass" at compile time, so I cannot simply call MyClass.main(String[]{}).

Answer 1

You use reflection to invoke methods (or create objects etc). Below is a sample to invoke main() method in MyClass. All you need to make sure is that MyClass is in the classpath.

Class<?> cls = Class.forName("MyClass");
Method m = cls.getMethod("main", String[].class);
String[] params = null; 
m.invoke(null, (Object) params);